The present invention relates to portable electric water coolers, and more particularly to such water coolers as may be utilized outdoors without danger of damage from freezing or water contamination.
Prior art water coolers are severely limited in their utilization by two considerations. The first consideration relates to ambient temperature; that is, prior art water coolers cannot be utilized in sub-freezing temperatures because the water would freeze and damage the unit. The second consideration relates to contamination of the water in the cooler. Specifically, it is desirable to utilize an electrically operated pump to force cool water from a spigot or faucet since doing so avoids the need for gravity feeding the output water and thereby requiring the water reservoir to be located above the output spigot. A typical prior art pump-operated water cooler is illustrated in U.S. Pat. No. 3,333,438 to Benua et al. In that patent an arrangement is provided whereby the water pump is operated by a switch mechanism located adjacent the output water faucet. The system is efficient for purposes of delivering output water but leaves the stored cool water and its output line in direct communication with ambient air when water is not being delivered from the cooler. This permits contaminants in the air to enter the output line and contaminate the water. In addition, larger particles in the ambient environment, such as might be present at a construction sight, can enter the output line and block water outflow.
It is therefore an object of the present invention to provide a portable water cooler which is suitable for use in sub-freezing environments.
It is another object of the present invention to provide a portable water cooler which prevents contaminants from entering the water system via the dispensing nozzle when water is not being delivered from the nozzle.